<?php 
echo "Hello ok";
echo'<br/>';
echo "Hello ok";
$j = "a";
echo'<hr/>';
var_dump(is_string(j));

#我是单行注释1

//我是单行注释2

/**
 * 我是多行注释
 */

#定义变量
echo'<hr/>';
echo "我是变量:";
$var1 = 1;
echo $var1;

#常量
echo'<hr/>';
echo "我是常量:";
const PII = 3.14;
echo PII;

#连接运算符
echo'<hr/>';
$a1 = "1";
$a2 = "2";
$a3 = "3";
echo $a1.$a2.$a3;
echo '<br/>';
echo $a1."个中国人";

#三目运算符
echo'<hr/>';
$a3 = 10;
$b = $a3 > 100 ? 10:3;
echo "目运算符结果为:".$b;

#if
echo'<hr/>';
echo "if分支控制";
echo '<br/>';
$day = 'sunday';
if ($day == 'sunday') {
    echo'go to work';
} else {
    echo 'go to school';
}

#for 循环
echo'<hr/>';
echo "for 循环";

#系统常用函数
echo'<hr/>';

























?>